<!--
 * @Author: your name
 * @Date: 2021-08-16 16:47:51
 * @LastEditTime: 2021-08-16 17:24:35
 * @LastEditors: Please set LastEditors
 * @Description: In User Settings Edit
 * @FilePath: \briup\2-HTML&CSS\day10\呼吸灯重写.html
-->
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>呼吸灯</title>
    <style>
        .one {
            width: 500px;
            height: 500px;
            padding: 50px;
            margin: 0 auto;
            background-color: rgb(15, 1, 39);
            box-sizing: border-box;
        }
        
        .two {
            height: 100%;
            border: 5px solid #fff;
            border-radius: 50%;
            padding: 20px;
            box-sizing: border-box;
            box-shadow: 0 0 5px 3px #fff;
        }
        
        .three {
            height: 100%;
            border: 30px solid #fff;
            border-radius: 50%;
            box-sizing: border-box;
            box-shadow: 0 0 7px 5px #fff;
        }
        
        body>.one:hover,
        body>.two:hover {
            animation-play-state: paused;
        }
        
        @keyframes change1 {
            from {
                padding: 50px;
            }
            to {
                padding: 20px;
            }
        }
        /* @keyframes change2 {
            from {
                padding: 20px;
            }
            to {
                padding: 50px;
            }
        } */
        
        .one {
            animation: change1 3s infinite 1s linear alternate;
        }
        
        .two {
            animation: change1 3s infinite 1s linear alternate-reverse;
        }
    </style>
</head>

<body>
    <div class="one">
        <div class="two">
            <div class="three">

            </div>
        </div>
    </div>
</body>

</html>